Slides in this set

Slide 1

Chemicals in the atmosphereSome are elements whereas (oxygen, nitrogen)some are compounds ( carbon dioxide)Water vapour varies so proportions are given asdry airThey are mainly molecular substancesStrong covalent bonds hold the atoms togetherwhereas weak forces hold the moleculestogether.Weak forces results in low melting and boilingpoints therefore they are mainly gases and liquidsThere are no free elections or ions meaning there is no chargebecause of this molecular substance don't conduct electricity.Low molecular mass = low M.P and low B.P…read more

Slide 2

Covalent bondingCovalent bonding is the sharing of electronsAtoms which outer shell are not already full share a pair ofelectrons to fill the outer shellThe bond is strong and needs a lot of energy to break it (highactivation energy) it is made due to electrostatic attractionbetween the positive nuclei and the negative electrons betweenthem CO2 Carbon need 4 electrons Oxygen needs 2 So two double covalent bonds O=C=O Often shown by ball and stick models…read more

Slide 3

The hydrosphereMade up of the water on the earth from oceans to puddles as wellas the compounds dissolved in the waterMany are ionic compounds such as salt e.g sodium chloride in seawaterPure water doesn't conduct electricity it is the ions dissolved in it,dissolving the ion frees the ions electrons to carry and electriccurrent same when it is melted.Ionic compounds are formed from charged particles, ions, oppositecharges attract to form a lattice giving theCrystals they form there cubic shape.Ionic bonds are strong taking lots of energy to break them giving them high melting andboiling points…read more

Slide 4

The lithosphereMade from the crust and part of the mantle below, made up ofminerals often containing silicon, oxygen and aluminium. Silicon andoxygen are mainly in the form of silicon dioxide.Different rocks contain different mineralsSilicon dioxide forms a giant covalent structure with no charged ions.As all the atoms are strongly bonded the substance is hard andinsoluble with high melting and boiling pointsSilicon dioxide makes up ­ quartz, sandstone and graniteSome minerals are really rare and therefore valuable,gemstones are an example of this ruby's, diamondsect. are all minerals with giant covalent structures.The structure makes them strong and when polishedshiny, attractive for jewellery.…read more

Slide 5

The BiosphereAll living things are formed from compounds of the same basic elements-Carbon, hydrogen, oxygen, nitrogen as well as phosphorus and sulphur.These make up the vital molecules of life-carbohydrates, fats ­ carbon hydrogen and oxygen (fat has morecarbon)-Proteins ­ always nitrogen sometimes sulphur-DNA ­ phosphorus and nitrogenThey are all molecular no ionsThe changes between spheres is shown in· flow charts· carbon cycle· nitrogen cycle· oxygen cycle…read more

Slide 6

Metals from MineralsMetal ores are rocks made of minerals from which metals can beextracted, the ore is often the oxide of the metal. Large amounts ofore need to be mined to obtain small percentages of metal this canbe calculatedStep 1 calculate the proportion of the metal =Step 2 find overall massThe more reactive the metals are harder to extractSome can be extracted by reduction with carbon or carbonmonoxide, oxygen is removed and given of as CO2Metals higher in the reactivity series than carbon have to beextracted using electrolysis. But only metals less reactive thancarbon can be reduced.…read more